A.L. Gelgor – Ph.D.(Eng.), Associate Professor, Higher School of Applied Physics and Space Technologies  of Peter The Great St. Petersburg Polytechnic University

E-mail: A_Gelgor@mail.ru

Nguyen Tan Hoang Phuoc – Post-graduate Student, Higher School of Applied Physics and Space Technologies  of Peter The Great St. Petersburg Polytechnic University E-mail: hoangphuoc1704@yahoo.com